Since 1985, the BLSA health evaluation has undergone major changes to improve the medical information about research participants. Two versions of the health questionnaire have been implemented. The initial questionnaire, introduced March 1, 1991, is used on participant's first visit to determine previous health complaints and problems. The interval history questionnaire, instituted March 1, 1993, is used for all subsequent visits to document changes in health complaints and status since their previous visit and to identify the effects of symptoms on daily living. The interval history provides the participant's previous responses to each item and allows the participant to indicate changes. The interval history questionnaire also includes an expansion of branching questions used for positive health complaints with questions assessing effects of these complaints on daily activities and emotional well being. The health evaluation also provides health screening for a number of research protocols. The unit has increased formalized handling of screening and research protocols; provided technical support to investigators in the development of research studies; and worked to minimize and/or prevent potential adverse outcomes or other problems. As part of our quality assurance program we have continued to assess the value of the new health questionnaire for BLSA research. Over the past year, we implemented a timed walk as a first step towards a quantitative functional assessment. The protocol was developed over the past two years in collaboration with Dr. Jack Guralnik, EDB. In a pilot study of about 100 BLSA participants, time required to walk both 10 and 50 feet at a normal pace, and as quickly as possible, begins to increase around 60 years of age, when chronic diseases and functional disability are not major problems in most of our participants. The test appears to be sensitive to early pathological changes, which should offer valuable information in understanding normal aging.